The present invention relates to a method and an apparatus for reducing operating costs and emissions in a pumping installation
There are numerous pumping installations in which multiple pumps are used to convey liquids. An example of such an installation is a methanol injection pumping installation associated with natural gas production facilities. As natural gas flows through piping, water vapour in the natural gas tends to condense and freeze, forming ice plugs in the piping. In order to prevent these ice plugs from forming, methanol is injected into areas of the piping that have been identified as being prone to the development of ice plugs. Each methanol injection pumping installation has a minimum of two pumps that inject methanol.
A factor in the economic viability of these pumping installations is rising operating costs relating to the operation and maintenance of the pumps. A further factor is the cost of complying with environmental standards relating to emissions from the pumps, as stricter environmental regulations are introduced.
What is required is a method and an apparatus for reducing operating costs and emissions in a pumping installation.
According to one aspect of the present invention there is provided a method for reducing operating costs and emissions in a pumping installation. A first step involves providing a flow dividing apparatus capable of dividing flow from a pump. The apparatus has a single inlet and two or more outlets. A second step involves coupling the flow dividing apparatus with a pump of the pumping installation and directing flow from the pump through the single inlet of the flow dividing apparatus. The pump will generate a flow stream from each of the two or more outlets and perform work that, in the absence of the flow dividing apparatus, would have to be performed by two or more pumps.
With the method, as described above, a single pump performs the work that is normally performed by two or more pumps. During proto-type testing a single pump was used in a methanol injection pumping installation to do work formerly performed by two pumps. The installation reduced both operating costs and emissions by more than 50%. Not only was a single pump doing the work of two, but the single pump was operating in a more efficient output range.
According to another aspect of the present invention there is provided an apparatus for reducing operating costs and emissions in a pumping installation. The apparatus includes a body having a single inlet and two or more outlets. Means are provided for coupling an input conduit from a pump to the single inlet. Means are provided for coupling an output conduit to each of the two or more outlets.
Although beneficial results may be obtained through the use of the apparatus, as described above, when a single pump is performing the work of two or more pumps, the flow rate for each application may not necessarily be equal. The relative flow output through the two outlets can be made unequal by adjusting the relative size of the passages. However, even more beneficial results may be obtained when means is provided to alter relative flow output through the two or more outlets.
There are various ways in which flow through the outlets can be altered and various valve configurations that can achieve the desired result. Beneficial results have been obtained through the use of a ball valve having a ball and seat. A compression spring is provided for exerting a biasing force upon the ball to maintain the ball engaged with the seat until a predetermined pump pressure is exerted to overcome the biasing force and permit the ball to be displaced. Some means must be provided for increasing and decreasing the biasing force exerted by the compression spring upon the ball. A preferred means for increasing and decreasing the biasing force is a rotatable pressure member extending into the body which acts upon the compression spring. Rotation of the rotatable pressure member in a first rotational direction extends the pressure member further into the body to increase the compressive force upon the compression spring. Rotation of the rotatable pressure member in a second rotational direction partially retracts the pressure member out of the body to decrease the compressive force upon the compression spring.
There are various ways in which the internal structure of the body can be configured to enable flow through the single inlet to be divided between two or more outlets. A configuration that has provided beneficial results and accommodated valving includes providing the inlet with an inlet passage that extends into the body. Each of the two or more outlets has a connective passage that extends through the body to communicate with the inlet passage, and a discharge passage that branches off from the connective passage.
Although beneficial results may be obtained through the use of the apparatus, as described above, the ability to alter relative flow output cannot be fully utilized unless the result of changes to relative flow output can be determined. In the absence of an indication as to relative flow output, relative adjustments become merely guesswork. Even more beneficial may, therefore, be obtained when means are provided to determine relative flow output through the two or more outlets. A convenient means for determining relative flow output has proven to be a pressure gauge on each of the two or more outlets that measures flow output pressure.
It is preferred that a pressure gauge also be placed on the single inlet that measures flow input pressure. This enables pump output pressure entering the single inlet to be monitored.